It is known to make use in computed tomography of multi-slice detectors and ray bundles with cone geometry for the purpose of scanning objects to be examined, in particular patients, and to carry out a 3D image reconstruction. In this process, integral absorption data of rays that penetrate the object to be examined are acquired and collected by multirow detectors of planar design, the detectors being moved spirally, together with a radiation source, about an object to be examined. Subsequently, the measured data are subjected to suitable filtering, and selected filtered data are back projected in order to produce tomographic images of the object to be examined. In this case, 3D image reconstruction means that for the purpose of back projection individual three-dimensional volume elements (=voxel) are considered in each case, and use is made in each case of the data that have been produced by rays and which have penetrated this voxel.
This mode of procedure is attended by the problem that because the collected data, which are firstly projected, for the purpose of simplifying calculation, onto a virtual detector—which lies on a plane that intersects the axis of rotation of the real detector and radiation source—are present in two dimensions and the filtering is intended to take place only in one dimension because of the resultant outlay on computation, there is no preferred direction to be seen in which the filtering should take place. If an unfavorable filtering direction is selected, it is therefore accompanied by losses in image quality.